
/**
 * 为日期对象增加函数
 * 日期格式化
 * 格式 YYYY/yyyy/YY/yy 表示年份
 * MM/M 月份
 * W/w 星期
 * dd/DD/d/D 日期
 * hh/HH/h/H 时间
 * mm/m 分钟
 * ss/SS/s/S 秒
 * @param {String} formatStr 日期格式字符串
 */
Date.prototype.format = function(formatStr)
{
    var str = formatStr;
    var Week = ['日', '一', '二', '三', '四', '五', '六'];

    str = str.replace(/yyyy|YYYY/, this.getFullYear());
    str = str.replace(/yy|YY/, (this.getYear() % 100) > 9 ? (this.getYear() % 100).toString() : '0' + (this.getYear() % 100));

    var month = this.getMonth() + 1;
    str = str.replace(/MM/, month > 9 ? month.toString() : '0' + month);
    str = str.replace(/M/g, month);

    str = str.replace(/w|W/g, Week[this.getDay()]);

    str = str.replace(/dd|DD/, this.getDate() > 9 ? this.getDate().toString() : '0' + this.getDate());
    str = str.replace(/d|D/g, this.getDate());

    str = str.replace(/hh|HH/, this.getHours() > 9 ? this.getHours().toString() : '0' + this.getHours());
    str = str.replace(/h|H/g, this.getHours());
    str = str.replace(/mm/, this.getMinutes() > 9 ? this.getMinutes().toString() : '0' + this.getMinutes());
    str = str.replace(/m/g, this.getMinutes());

    str = str.replace(/ss|SS/, this.getSeconds() > 9 ? this.getSeconds().toString() : '0' + this.getSeconds());
    str = str.replace(/s|S/g, this.getSeconds());

    return str;
};